From: Aqua Fina <aquafina@...>
Date: 2006-08-10T05:57:16+09:00
Subject: Re: Simple looping question

Max Muermann wrote:
> equire 'yaml'
> require 'enumerator'
> 
> data = YAML::load File.read('data.yml')
> data.entries.sort_by{|date, *| date }.each_cons(2) do  | first, second |
>  date_first = DateTime.parse(second[0].to_s)
>  date_second = DateTime.parse(first[0].to_s)
>  duration = date_first - date_second
>  miles = second[1][1] - first[1][1]
>  miles_per_gallon = miles / first[1][0]
>  p "The #{first[1][0]} gallons of gas purchased on
> #{date_first.strftime('%m/%d/%Y')} lasted #{duration.to_i} days. The
> mileage was #{miles_per_gallon} miles per gallon."
> end
> 
> The key here is the each_cons coming from the enumerable mixin, which
> iterates the array in pairs of twos.

Brilliant. That enumerator mixin is crazy awesome. Thanks.

> Disclaimer: I am a German living in Australia, so if I got the date
> format or the miles per gallon calculation wrong, blame the non-metric
> system.
> 
> Max


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